PERTH: The United States beat Japan 2-1 at the Hopman Cup after an illness withdrawal by one of the Japanese players, but the win may come at a cost after Jack Sock injured his hip.
Sock slipped on the court during the first set of his match Tuesday against Yuichi Sugita, grabbing his hip. He was forced to retire at 1-1 in the second set after losing the first set 7-6 (1).
There was no immediate word on the seriousness of the injury, and whether it might affect his play for the rest of the Hopman Cup, or for the Australian Open which begins Jan. 15 in Melbourne.
The U.S. team had already led 1-0 after Japan's female player, Naomi Osaka, withdrew with an unspecified illness, handing CoCo Vandeweghe a 6-0, 6-0 win.
The Americans were also awarded the Fast4 mixed doubles match 4-0, 4-0 because Osaka was not able to compete.
Osaka's place in both matches was taken by 19-year-old local player Maddison Inglis, who was woken up at 8:30 a.m. by tournament officials who told her she would be required to play.
Vandeweghe teamed up with her coach and 1987 Wimbledon champion Pat Cash in the meaningless Fast4 mixed doubles match against Inglis and Sugita.
Later Tuesday, Roger Federer and Belinda Bencic will attempt to make it two wins in a row for Switzerland in Group B when they play Russia. Switzerland beat Japan and the U.S. defeated Russia on Saturday.
The U.S. and Switzerland play on Thursday in a match that could decide which team advances from the group to Saturday's final.
In Group A matches on Wednesday, Canada plays Germany and Australia takes on Belgium. Australia beat Canada and Germany defeated Belgium in the opening round.